www.iFourWinns.com

A strange one, but please bear with me here...

I was kneeling next to my Bravo 3 yesterday and when the soft part of my arm touched the prop's, I'd get an electrical tingle through my arm.
It's only when my (near new) CTEK battery chargers are plugged in and I've wired them directly to the building's power outlet to eliminate the boat's shore power - it still tingles my arm.

I got my multimeter & grounded it on my pickup truck and got 50 millivolts (1000 millivolts to a volt) on the prop.
Disconnect the batt charger & get 150 millivolts & no arm tingle?!
I can replicate this every time.

I have a Mercathode and was wondering whether this small voltage is normal & whether it changes when a charger is connected?
Any tips?

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

A. Are you using a CAR charger vs a marine battery charger?
B. Does this boat have a shore power connection?
C. Could the Hot & Neut. be swapped out?

50 millivolts or 150 millivolts does not seem like enough to feel anything. I can grab both terminals of a 12v battery and not feel anything.

Your pickup might not be a good ground reference since it sits on rubber tires. Are there any metal pipes or handrails, or similar with significant contact with the earth? Or use the ground hole in a nearby electrical outlet.

Can you check the voltage meter readings on both AC and DC settings? (from prop to good earth ground) Perhaps there is a pulsing voltage that will show up on AC that does not show up on the DC meter.

_________________

"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

I am using a CTEK car battery charger & the boat does have shore power.
Is there any difference between a marine charger & a car charger?! I can't see anything!

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

A Faulty ground on the electrical cord can cause this.

Difference between a car and marine charger

Many chargers especially the less-expensive ones don’t always completely shut down.Marine chargers go into a float mode.
While using a auto charger and plugged into shore power you can cause electrical problems for other boats using the same circuit as you.

It's one of the worst offenders & causes of stray current corrosion due to their internal architecture which very often does not isolate AC & DC sides like a marine charger will.((AC Ground and neutral wires being tied together)
Most of the car/auto type battery chargers use what is often referred to as an "autoformer" or autotransfomer. These are transformers with just one winding. They work on land.
Because of this single winding they share a common internally. Portions of the same winding act as both the primary and the secondary. This is bad news and not how a "marine" charger is built.

With a marine charger all AC source current runs through the AC hot wire of the charger and is fully returned to shore via the white/neutral wire. The "case" is also grounded to the ships DC ground just in case it becomes energized in an internal fault. Again this = a big NO !!!! DO NOT USE AN AUTOMOTIVE CHARGE ON A BOAT......

If the car charger has a two prong plug, many do, especially the older ones we all seem to have lying around the house, these can inadvertently become reversed. This is especially true if your boat has old AC outlets. If the AC feed neutral & hot are reversed the ships DC negative bus can now become 120V AC with a car charger. You don't want to be a swimmer near a boat with a cheap car charger on-board. You also do not want to be the cause of an electric shock drowning

Thanks Thalasso.
I have this CTEK charger:
http://www.ctek.com/au/en/chargers/MXS%205.0
Is this deemed an auto charger?!

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

It should be ok. It's non-sparking, reverse-polarity protected and short-circuit proof. The only thing is you need to make sure it goes into maintenance mode.
If the charger has not switched to maintenance charge within 72 hours, the charger must be disconnected manually. If the charger has not switched to maintenance charge after 48 hours and the green lamp is lit, this is a sign that something is wrong.

Thanks Thalasso.
It does go in to maintenance mode and will re-charge if the voltage drops.
It's only a little 5 amp on my 90AH battery, but charges within 6 hours to full capacity.
Back to the drawing board!

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

Did some further testing yesterday.

Isolated both chargers independently & still get zapped by the outdrive.
Ran a long extension lead to a neighboring building (it has an earth stake in the ground) & still get zapped.
I used my multimeter & grounded it on a nearby water pipe. The outdrive has 100mv.
My charger has only a 2 prong plug & have seen some larger chargers with a 3 prong plug (with earth pin).
Would changing to a 3 prong charger eliminate this zapping?

Are we sure this isn't a normal function of the Mercathode?!

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

I've not felt it with my Mercathode but I've never tried before. I'm not sure to tell if the system is working properly or not either though.

_________________
Terry
Current: 07 Crownline 255 CCR cuddy - 350 Mag MPI/B3 "Casi Cielo"

Previous:97 245 Sundowner 5.7GI/SX

Tow vehicle: 1986 GMC 2500 Camper Special 454/TH400

Needs to be in the water

MerCathode System Testing - MerCstuff
www.mercstuff.com/mercathodetest.htm

Disconnect the Mercathode positive wire and see if you feel the tingling. The controller for the mercathode should be on top of the engine near the oil filter brkt.
You don't say what year but it's either blue or red in color. The older one's were black
There will be 4 wires on the back.

Upon further research, I've found that the culprit might be my charger itself.
I've read (online) that this has been experienced before on other boats, when using a charger with a 2 prong plug (as opposed to 3 prong).
I'll try borrow a 3 prong charger to test over the weekend & also test the Mercathode if that test fails.

Might be on to something here?!

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

So I bought a new Victron Energy IP67, 25A, 3 pin charger last week & installed it yesterday.
Drum roll, please...

No more tingling!

I spoke to a few other qualified Electricians and they mentioned that a boat uses a Floating Ground and a 3 pin plug (with earth pin) could hypothetically stop the tingling/ leakage.
Like my handy work?

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS